Master Free Online Diagramming with Diagrams (draw.io): A Complete Guide

Introduction

Hello everyone, I’m Su San, back again to share a useful tool.

Many readers have asked which tool I use to create the clean, fresh‑looking diagrams in my articles.

1. Which tool do I use?

Commonly used diagram tools include visio and process on, both of which are paid or have limited free features.

For a completely free, online, and powerful alternative, I use diagrams (also known as draw.io).

The tool’s website is https://app.diagrams.net/ (formerly https://draw.io/ ). An offline version is available but requires a license, so I mainly use the online version.

2. How to open the diagram interface

Enter the URL https://draw.io/ in a browser. The first load may be slow due to initialization.

A dialog appears asking where to store the diagram. The options are:

OneDrive

Device (local storage)

GitHub

GitLab

I usually choose Device for convenience, but GitHub is also a good option.

After confirming, you can create a new diagram or open an existing one.

3. Components of the diagram interface

3.1 Menu Bar

File

: New, Open, Save, Export, Print, etc. Edit: Undo, Redo, Cut, Copy, Paste, Delete, Find, Replace, etc. View: Reset layout, Outline, Layers, Grid, Fullscreen, etc. Arrange: Order, Align, Group, etc. Extras: Themes, Plugins, Settings, etc. Help: Search, Shortcuts, About.

3.2 Toolbar

The toolbar provides quick access to functions such as zoom, undo/redo, shape ordering, background color, font color, connectors, shadows, tables, and fullscreen.

3.3 Shape Library (left panel)

The left panel contains default shape categories (e.g., General, Flowchart). You can click “More Shapes” to add additional libraries such as iOS shapes.

3.4 Canvas (center area)

This is where you draw your diagrams. You can drag shapes from the left panel onto the canvas, duplicate existing shapes, and enable a grid for alignment.

Right‑clicking on empty canvas space shows generic options, while right‑clicking a shape reveals shape‑specific actions.

3.5 Style Panel (right side)

The style panel lets you customize the appearance of selected shapes, including fill color, border, opacity, and text styling.

3.6 Bottom Bar

The bottom bar displays the current page name. You can add, rename, reorder, or delete pages using the three‑dot menu or the plus button.

Summary

Diagrams (draw.io) is a free, powerful online diagramming tool with a rich UI that includes a menu bar, toolbar, shape library, canvas, style panel, and bottom navigation. It enables you to create professional flowcharts without cost, and the interface is intuitive once you explore its features.